Anyone used Preside email as a mail client on iOS?

I am specifically talking about [this app](https://apps.apple.com/ca/app/preside-email/id808514898) that claims to be privacy focused and that everything is stored locally on your device. I am looking for a privacy-based iOS email client that’s not the Gmail app for work related things.

According to the App Store it has very good reviews and has been active for a long time. Run by a husband and wife apparently.

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